Etimology of the word bliaut

bliaut: Old French, of Germanic Origins. The root of the modern word
blouse.
Also spelled Bliaud, Bliaus, Bliant, Bliaunt, Bliand. From
Cunnan

bliaud: Italian. devived from the French word bliaud which
is from
the Old French blialt. The earliest known usage of bliaud in French dates
from the 12th century.
From MyEtymology

blouse: "Fr. blouse is from Old Fr. bliaus which is the plural of
bliaut"
From Folk-Etymology by Abram Smythe Palmer

bliaut, blizant, blial, bliau: "(robe, habit, justaucoprs),
blezo bleso (tunique), Old French
bliaut bleaut bliaus bliaux (justaucorps, manteau), Spanish Portuguese
brial a rich petticoat, L.L.
bliaudus blialus, bliaus. The Middle High German blialt bliât
denotes the stuff merely, so also in Old French. Diez
suggests that the root bli or blid is oriental, and Mahn refers to Persian
baljas a plain garment, from
Ar. (Arabic?) root balâ to wear a garment. The French blouse, Pic.
(Picardian?) bleude, Norman plaude (cf. the
forms blizant, bliaus &c.) is the same word. Ducange derives bliaud &c. from
the W. (Welsh?) blaind a fine
linen-stuff, Old English bleaunt, blehand." Mahn wrote Untersuchungen auf dem Gibiete der
Romanishen Sprachen. Diez wrote Introduction to the Grammar of the Romance Languages (also in German). From
Bonkin.

Overall, the word bliaut appears in various forms many modern and medieval languages which
suggests it was known throughout Europe. Many Old French references appear
which suggests the bliaut may have been most popular in France. The word may have originally
come from the Middle East which might suggest it traveled to europe with silks during the 12th
Century as a result of the Crusades.